Doctoral Dissertations

Brian C. Bock

Date of Award

12-1984

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Psychology

Major Professor

Gordon M. Burghardt

Committee Members

A. Stanley Rand, Gary McCracken, Sandy Echternacht

Abstract

The green iguana (Iguana iguana) population located around Lake Gatun, Panama, faces a scarcity of nesting sites. Female iguanas from this population gather annually at the available sites to nest in aggregations and the hatchling iguanas emerge serveral months later to rapidly disperse away from these sites. This study investigated nesting site fidelity of the iguanas in this population over five nesting seasons and also studied the movements of female and hatchling iguanas from the nesting sites. Evidence for a genetic structuring of the population related to these movements was also gathered using allozyme analysis.

An intensive mark-recapture effort of female iguanas over five nesting seasons produced evidence of strong nesting site fidelity in these lizards. Some iguanas may have nested solitarily, however, and females also explored and occasionally nested in new sites that became available to them during this study. Thus, the site fidelity demonstrated was not absolute, although most female iguanas returned to the same nesting site year after year.

Investigations of female iguana nestings movements and hatchling dispersal demonstrated that both involved rapid movements of comparable distances away from the nesting sites. Females followed over two successive nesting seasons seemed to be returning to established home areas. Several female iguanas that had been marked as hatchling iguanas were recaptured as nesting females at the site near where they were first captured.

Electrophoretic analysis of blood and tissue samples obtained from female iguanas captured at the nesting sites revealed significant allele frequency differences among these iguanas at one of the two polymorphic loci inspected. The evidence suggests that female iguanas associated with the most isolated nesting aggregation may belong to a distinct local population that is somewhat reproductively isolated from the population associated with the remaining two nesting sites studied. The nesting site fidelity exhibited by female iguanas and the movement patterns documented for both female iguanas and dispersing hatchlings corroborate this electrophoretic evidence and suggest that limited dispersal and nesting site fidelity are producing a restriction of gene flow between these two local demes.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS